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Date: Wed, 21 Jun 2006 08:00:30 +0000 (GMT+00:00)
From: "Vladimir Strigun (JIRA)" <jira@apache.org>
To: harmony-commits@incubator.apache.org
Subject: [jira] Commented: (HARMONY-630) Performance improvement for
 BufferedReader and LineNumberReader classes
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    [ http://issues.apache.org/jira/browse/HARMONY-630?page=comments#action_12417055 ] 

Vladimir Strigun commented on HARMONY-630:
------------------------------------------

Hi Nathan,

values are in milliseconds, so the less is better. As far as I see from posted values with new version we have some improvement in hsqldb and xalan benchmarks. 

> Performance improvement for BufferedReader and LineNumberReader classes
> -----------------------------------------------------------------------
>
>          Key: HARMONY-630
>          URL: http://issues.apache.org/jira/browse/HARMONY-630
>      Project: Harmony
>         Type: Improvement

>   Components: Classlib
>     Reporter: Vladimir Strigun
>     Assignee: Nathan Beyer
>     Priority: Minor
>  Attachments: Harmony-630.patch
>
> Analysis of BufferedReader and LineNumberReader was made by our team. These classes are widely used and it's recommended, for instance, that any character IO should go through BufferedReader for better performance. Therefore it should perform well and should not itself be a bottleneck. 
> We have identified opportunity to increase performance of mentioned classes. Publicly available bench DaCapo[1] was used for performance measurement and we found that DaCapo:hsqldb benchmark performance can be improved within small modification of java.io.BufferedReader and java.io.LineNumberReader classes. Main idea of the patch (I will attach it soon) is to remove StringBuilder allocation from "malloc"-hot methods readLine. 
> Here is result of DaCapo execution with patched and original versions of classlib+J9:
> Build	Dacapo: fop	Dacapo: hsqldb	Dacapo: xalan	Dacapo: chart	
> original	712.020	27232.647	4201.449	22573.192	
> patched	715.152	26703.966	4161.018	22580.771	
> [1] http://www-ali.cs.umass.edu/DaCapo/gcbm.html

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